Rectangular Polyline 题目大意 给定 \(h\) 条长度分别为 \(l_1,l_2,--,l_h\) 的水平线段以及 \(v\) 条长度分别为 \(p_1,p_2,--.p_v\) 的竖直线段,将这些线段水平竖直交替地首尾相连组成一个多边形,满足任意两条线段不相交或交点为各自的端点.可能无解. 题意分析 是否有解 首先考虑有解的必要条件. 由于题目要求线段要交替摆放,所以线段的数量肯定满足 \(h=v\) ,否则无解. 其次,由于最后要首尾相连,设集合 \(X\) 为水平线段…

由于两种线段要交替出现,有解的必要条件即为$h=v$(以下均记为$n$) 进一步的,再假设两种线段依次对应于向量$(a_{i},0)$和$(0,b_{i})$,根据题意要求向量长度为给定值且和为0,那么也即有$|a_{i}|=l_{i},|b_{i}|=p_{i}$且$\sum_{i=1}^{n}a_{i}=\sum_{i=1}^{n}b_{i}=0$ 使用背包判定是否存在这样的$a_{i}$和$b_{i}$,若不存在即无解,若存在则再求出任意一组 (可以证明此时一定有解,以下即为构造) 若$a…

Rectangular Polygons 题目链接: http://acm.hust.edu.cn/vjudge/contest/129733#problem/G Description In this problem, we will help the Faculty of Civil Engineering. They need a software to analyze ground plans of buildings. Specifically, your task is to det…

D. Polyline 题目连接: http://www.codeforces.com/contest/617/problem/D Descriptionww.co There are three points marked on the coordinate plane. The goal is to make a simple polyline, without self-intersections and self-touches, such that it passes through…

这个专栏开始介绍一些<ACM国际大学生程序设计竞赛题解>上的竞赛题目,读者可以配合zju/poj/uva的在线测评系统提交代码(今天zoj貌似崩了). 其实看书名也能看出来这本书的思路,就是一本题解书,简单暴力的通过题目的堆叠来提升解决编程问题的能力. 那么下面开始探索吧. poj1037: Description Background For years, computer scientists have been trying to find efficient solutions to…

今天老师(orz sansirowaltz)让我们做了很久之前的一场Codeforces Round #257 (Div. 1),这里给出A~C的题解,对应DIV2的C~E. A.Jzzhu and Chocolate time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has a big rectangular cho…

A Rectangular Barn Mircea Pasoi -- 2003 Ever the capitalist, Farmer John wants to extend his milking business by purchasing more cows. He needs space to build a new barn for the cows. FJ purchased a rectangular field with R (1 ≤ R ≤ 3,000) rows numbe…

Input file: polyline.in Output file: polyline.out Time limit: 1s Memory limit: 128M 有若⼲个类似于下⾯的函数: 定义 n 个函数 y1(x), ..., yn(x) 的对于任意 x 的总和 s(x) = y1(x) + ... + yn(x),很容易发现 s(x) 的图象是多段线组成.给你 n 个函数,你的任务是找出 s(x) 图象不等于 180 度的⾓的个数. Input 第⼀⾏⼀个整数 n,表⽰函数的个数.接…

CSU-2116 Polyline Simplification Description Mapping applications often represent the boundaries of countries, cities, etc. as polylines, which are connected sequences of line segments. Since fine details have to be shown when the user zooms into the…

                                                                       C. A Problem about Polyline                                                                                time limit per test 1 second                                            …